The acute phase of HIV-1 infection may be the time when the subsequent course of infection is determined. Increased viral replication and/or decreased host immunity may predispose to a more disease course. The sites for viral replication acutely are also unclear. This protocol will examine host immune responses (neutralizing antibodies, helper T cells, killer T cells) and infected cells (dendritic cells, T cells, monocytes) early in the course of HIV-1 infection.